The invention relates to the harnessing of the items and more particularly to the realization of efficient, low-cost, high strength harnessing devices which are easy to use.
Harnessing devices are widely used for the bundling of objects. Such devices are typically formed with a serrated strap that is fitted to an apertured head containing an internal pawl or locking tang that engages the serrations of the strap. Other harnessing devices are in the form of an apertured strap fitted to a buckle-like head, with a tongue that enters the apertures of the strap.
Harnessing devices with serrated straps have the disadvantage of being only as secure as their pawls. Where the items that are harnessed are heavy or are subjected to rough handling, the items can become accidentally released, for example, by pawl failure. Attempts have been made to strengthen serrated strap devices, without achieving the desired end result of providing enhanced security against accidental release of harnessed items. Similar objections apply to harnessing devices with buckle-like heads. In these devices, a tongue which enters the strap apertures rests against the head of the buckle near its opening and is deflected by the strap. The tongue is typically a cantilever attachment to the buckle-like head, which is inadequate in most harnessing applications.
Representative harnessing devices are disclosed in U.S. Pat. Nos. 515,747; 2,977,145; 3,030,131; 3,102,311; 3,106,028; 3,127,648; 3,140,139; 3,189,961; 3,339,246; 3,368,247; 3,486,201; 3,457,598; 3,537,146; Re 26,492; 3,542,321; 3,588,962; 3,598,442; 3,627,300; 3,654,669; 3,660,869; 3,731,347; 3,816,878; 3,840,246; 3,872,547, 3,906,593; 3,908,233; 3,949,449; 3,965,538; 3,991,444; 3,996,646; 4,001,898; 4,003,106; 4,128,919; 4,135,749; 4,136,148; and 4,137,606.
In order to avoid and overcome many of the difficulties associated with the foregoing kinds of harnessing devices, ladder straps and associated locking tangs have been developed of the kind disclosed in U.S. Pat. No. 3,766,608, which issued Oct. 23, 1973. The ladder strap device represents a significant improvement over the serrated strap and other harnessing devices. It can accomplish substantially the same functions as a serrated strap device at a considerably lower cost. The ladder strap can be produced with a significant saving in material and can be stretched to reorient its molecular structure and strengthen its constituents without strap distortion, as would occur if an attempt were made to stretch a serrated strap.
Notwithstanding its advantages, however, the ladder strap is not suitable for every bundling application. The precision with which the ladder strap tie can be adjusted is controlled by the spacing between its rungs. Since it is advantageous for the strap of the ladder tie to be stretched in order to reorient its crystalline structure, the stretching often produces a separation of subsequent rungs which reduces the precision with which such a tie can be used in the bundling of objects. In addition the ladder tie makes use of a deflectable pawl which extends between adjoining rungs. The locking of the pawl with the strap results in the application of substantially shear pressures to the pawl.
Accordingly, it is an object of the invention to provide for the secure harnessing of items. A related object is to achieve secure harnessing without the need for a complex harness configuration. Other related objects are to achieve a cost effective, light weight, minimum material, and precisely adjustable device.
A further object of the invention is to provide a harnessing device which is efficient, accurate and rapid to use. A related object is to provide a suitable structure without an undue increase in bulk. Another related object is to overcome the difficulties associated with harnessing devices. Still another related object is to produce a structure that has sufficient mass for efficient use while being sufficiently light in weight so as not to interfere with harnessing operations.
A further object of the invention is to achieve secure anchoring of the strap in the head.
Still another object of the invention is to achieve precision control over the strap configuration in order to realize precise bundling of objects.